SciCombinator

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Concept: Alkaloid

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The tropane and granatane alkaloids belong to the larger pyrroline and piperidine classes of plant alkaloids, respectively. Their core structures share common moieties and their scattered distribution among angiosperms suggest that their biosynthesis may share common ancestry in some orders, while they may be independently derived in others. Tropane and granatane alkaloid diversity arises from the myriad modifications occurring to their core ring structures. Throughout much of human history, humans have cultivated tropane- and granatane-producing plants for their medicinal properties. This manuscript will discuss the diversity of their biological and ecological roles as well as what is known about the structural genes and enzymes responsible for their biosynthesis. In addition, modern approaches to producing some pharmaceutically important tropanes via metabolic engineering endeavors are discussed.

Concepts: Agriculture, Evolution, Biology, Species, Fungus, Cocaine, Alkaloid, Tropane

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Kratom (or Ketum) is a psychoactive plant preparation used in Southeast Asia. It is derived from the plant Mitragyna speciosa Korth. Kratom as well as its main alkaloid, mitragynine, currently spreads around the world. Thus, addiction potential and adverse health consequences are becoming an important issue for health authorities. Here we reviewed the available evidence and identified future research needs. It was found that mitragynine and M. speciosa preparations are systematically consumed with rather well defined instrumentalization goals, e.g. to enhance tolerance for hard work or as a substitute in the self-treatment of opiate addiction. There is also evidence from experimental animal models supporting analgesic, muscle relaxant, anti-inflammatory as well as strong anorectic effects. In humans, regular consumption may escalate, lead to tolerance and may yield aversive withdrawal effects. Mitragynine and its derivatives actions in the central nervous system involve μ-opioid receptors, neuronal Ca(2+) channels and descending monoaminergic projections. Altogether, available data currently suggest both, a therapeutic as well as an abuse potential.

Concepts: Nervous system, Brain, Nicotine, Morphine, Addiction, Alkaloid, Kratom, Mitragynine

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The first total synthesis of the dimeric berberine alkaloid ilicifoline (ilicifoline B) is reported. Its carbon skeleton is constructed from ferulic acid, veratrole, and methanol. The synthesis reported herein employs starting materials solely derived from wood. The natural product is thus constructed entirely from renewable resources. The same strategy is applied to a formal total synthesis of morphinan alkaloids. The use of wood-derived building blocks (xylochemicals) instead of the conventional petrochemicals represents a sustainable alternative to classical synthetic approaches.

Concepts: Oxygen, Alcohol, Total synthesis, Natural resource, Paclitaxel, Alkaloid, Natural products, Natural capital

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Complexation of alkaloids is an important strategy plants utilize to facilitate storage in vacuoles and avoid autotoxicity. Previous studies have implicated hydroxycinnamoyl quinate esters in the complexation of purine alkaloids in Coffea arabica. The goal of this study was to determine if Erythroxylum coca uses similar complexation agents to store abundant tropane alkaloids, such as cocaine and cinnamoyl cocaine. Metabolite analysis of various E. coca organs established a close correlation between levels of coca alkaloids and those of two hydroxycinnamoyl esters of quinic acid, chlorogenic acid and 4-coumaroyl quinate. The BAHD acyltransferase catalyzing the final step in hydroxycinnamoyl quinate biosynthesis was isolated and characterized, and its gene expression found to correlate with tropane alkaloid accumulation. A physical interaction between chlorogenic acid and cocaine was observed and quantified in vitro using UV and NMR spectroscopic methods yielding similar values to those reported for a caffeine chlorogenate complex in C. arabica. These results suggest that storage of cocaine and other coca alkaloids in large quantities in E. coca involves hydroxycinnamoyl quinate esters as complexation partners.

Concepts: Coffee, Caffeine, Cocaine, Alkaloid, Chlorogenic acid, Quinic acid, Tropane, Tropane alkaloid

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Harmane (HA) is a β-carboline alkaloid derived from the Peganum harmala plant which induces memory impairment. On the other hand some of the investigations showed that β-carboline alkaloids inhibit NO production. Thus, the aim of the present study was to investigate the role of nitrergic system of the dorsal hippocampus (CA1) in HA-induced amnesia in male adult mice. One-trial step-down passive avoidance and hole-board apparatuses were used for the assessment of memory retrieval and exploratory behaviors respectively. The data indicated that pre-training intraperitoneal (i.p.) administration of HA (12 and 16mg/kg) decreased memory acquisition. Sole pre-training or pre-testing administration of L-NAME, a nitric oxide synthesis inhibitor (5, 10 and 15μg/mice, intra-CA1) did not alter memory retrieval. On the other hand, pre-training (10 and 15μg/mice, intra-CA1) and pre-testing (5, 10μg/mice, intra-CA1) injections of L-NAME restored HA-induced amnesia (16mg/kg, i.p.). Furthermore, neither sole pre-training nor pre-testing administration of l-arginine, a NO precursor (3, 6 and 9μg/mice, intra-CA1), altered memory retrieval. In addition, pre-testing (6 and 9μg/mice, intra-CA1), but not pre-training, injection of l-arginine increased HA-induced amnesia (16mg/kg, i.p.). These results suggest that the nitrergic system of CA1 is involved in HA-induced amnesia.

Concepts: Nitrogen, Hippocampus, Nitric oxide, Amnesia, Alkaloid, Harmal, Harmala alkaloid, Harmine

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Multiple myeloma (MM) is an incurable B cell neoplasm causing significant morbidity and mortality. Despite recent advances in the MM-treatment, the disease still remains incurable; necessitating a search for new therapeutic agents. Therefore, Strychnos nux-vomica L. root extract (SN) was screened using the human MM-cell line, U266B1. SN-extract demonstrated anti-proliferative effect in a time- and dose-dependent manner. Morphological studies, cell cycle analysis by FACS indicate apoptosis. Furthermore, assessment of signaling molecules like IL-6 (interleukin-6) and CD-138 (Sydencan-1) confirmed apoptosis. The anti-proliferative activity of SN-extract is associated with apoptosis, which is likely due to the presence of alkaloids, strychnine and brucine, which have been identified by MALDI-TOF-MS and RP-HPLC analysis.

Concepts: Multiple myeloma, Cancer, Disease, Cell cycle, Alkaloid, Strychnine, Strychnine tree, Strychnos

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Changes occurring in phenolic compounds and purine alkaloids, during the growth of seeds of cacao (Theobroma cacao) cv. Trinitario were investigated using HPLC-MS/MS. Extracts of seeds with a fresh weight of 125, 700, 1,550 and 2,050 mg (stages 1-4, respectively) were analysed. The phenolic compounds present in highest concentrations in developing and mature seeds (stages 3 and 4) were flavonols and flavan-3-ols. Flavan-3-ols existed as monomers of epicatechin and catechin and as procyanidins. Type B procyanidins were major components and varied from dimers to pentadecamer. Two anthocyanins, cyanidin-3-O-arabinoside and cyanidin-3-O-galactoside, along with the N-phenylpropernoyl-L-amino acids, N-caffeoyl-L-aspartate, N-coumaroyl-L-aspartate, N-coumaroyl-3-hydroxytyrosine (clovamide) and N-coumaroyltyrosine (deoxyclovamide), and the purine alkaloids theobromine and caffeine, were present in stage 3 and 4 seeds. Other purine alkaloids, such as theophylline and additional methylxanthines, did not occur in detectable quantities. Flavan-3-ols were the only components to accumulate in detectable quantities in young seeds at developmental stages 1 and 2.

Concepts: Caffeine, Catechin, Flavonoid, Phenolic compounds in wine, Alkaloid, Xanthine, Theobromine, Theobroma cacao

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Fungi are some of the most important organisms in the production of bioactive secondary metabolites. This success is related to the advances in biotechnology and also to the possibility of working with techniques such as the “OSMAC” (one strain-many compounds) to achieve different fungal secondary metabolites profiles upon modifying the culturing conditions. Using this approach, the fungal species Paecilomyces lilacinus was cultivated in potato dextrose broth under 14 different fermentative conditions by adding the bacterium Salmonella typhimurium to the growing medium in order to provide biotic stress. S. typhimurium was added alive or after inactivation by autoclave or microwave irradiation in different stages of fungal growth. Extracts were prepared by liquid-liquid extraction using ethyl acetate, a medium polarity solvent in order to avoid extracting culturing media components. Production of fatty acids of relevance for the pharmaceutical and food industries was enhanced by the modified fermentative conditions and they were identified and quantified. The extracts were evaluated for acetylcholinesterase inhibition and the more active extract (91±2.91% inhibition) was prepared in large scale. From this active P. lilacinus extract, a novel pyridone alkaloid, named Paecilomide, was isolated and its structure was elucidated by modern nuclear magnetic resonance techniques and mass spectrometric analyses. Paecilomide (1) was also evaluated for acetylcholinesterase inhibition, presenting 57.5±5.50% of acetylcholinesterase inhibition.

Concepts: Bacteria, Enzyme, Biology, Fungus, Ethanol, Paecilomyces, Alkaloid, Paecilomyces lilacinus

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Cut to the chase: Direct formation of an enehydrazine, an intermediate in the classic Fischer indole synthesis, solves the regioselectivity problem associated with indolization. This approach not only achieves selective synthesis of indoles through proper selection of the vinyl halide, but also leads to quick construction of desoxyeseroline and esermethole, as well as the key structural motif in the Akuammiline alkaloid vincorine.

Concepts: Functional groups, Indole, Bartoli indole synthesis, Alkaloid, Fischer indole synthesis, Tryptamine, Leimgruber-Batcho indole synthesis

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The racemic modification of the Aspidosperma alkaloid limaspermidine (1) has been prepared in ten steps including one involving a Raney-cobalt-mediated tandem reductive cyclization of nitrile 8 to give the tetracyclic system 9b. Compound (±)-1 has been converted over two steps into (±)-1-acetylaspidoalbidine [(±)-13].

Concepts: Chemical synthesis, Alkaloid, Reserpine